Atomic force microscope with optional replaceable fluid cell

ABSTRACT

An atomic force microscope which is readily useable for researchers for its intended use without extensive lost tome for setup and repair. The probe used therein is a cantilevered optical lever which imparts surface information in a gentle and reliable manner by reflecting an incident laser beam. The probe (20) is carried by a replaceable probe-carrying module (48) which is factory set up and merely inserted and fine tuned by the user. Calibration tools are provided to make initial set up and fine tuning of the microscope a simple and straightforward operation requiring little or no technical talent. The probe module (48) is mechanically coupled to a probe module support (38) so that the probe is substantial alignment with a deflection detection system (26, 66). &lt;IMAGE&gt;

This invention was made with Government support under Contract No.N00014-87-K-2058 awarded by the Office of Naval Research. The Governmenthas certain rights in this invention.

BACKGROUND OF THE INVENTION:

This invention relates to scanning microscopes used for imaging thetopography of surfaces and, more particularly, to an atomic forcemicroscope having extended use capabilities comprising, a horizontalbase member; a scan tube vertically supported at a bottom end by thebase member and having a top surface for holding a sample to be scannedand moveable in x-, y-, and z-directions as a result of scanningvoltages applied thereto; first support means extending upward from thebase member; a sample holding block having a chamber therein, the sampleholding block having a first bore communicating with the chamber througha bottom surface, a second bore communicating with the chamber through atop surface, and a third bore communicating with the chamber at an acuteangle to the second bore, the sample holding block being positioned withthe scan tube passing through the first bore and supported by the firstsupport means; second support means extending upward from the bottomsurface into the chamber, a probe-carrying module having a probeattached thereto and extending downward therefrom at an acute angle witha tip of the probe positioned to contact a sample mounted on the topsurface of the scan tube, the probe carried by the probe-carrying modulecomprising a substrate attached to the probe-carrying module and a pairof arms of a smooth-surfaced, minimally self-biased materialcantilevered outward from a bottom front edge of the substrate in aV-shape to form an optical lever, the pair of arms having a probe pointat the apex of the V-shape thereof; a source of a laser beam mounted fordirecting the laser beam down the second bore from the top surface ofthe sample holding block to strike the probe and be reflected down thethird bore to an outer end thereof; and, photoelectric sensor meanshaving an active surface positioned over the outer end of the third borefor developing an electrical signal at an output thereof reflecting theposition on the active surface at which the laser beam strikes theactive surface.

The family of scanning probe microscopes that have been introduced tothe scientific community of recent years is broadening the frontiers ofmicroscopy. As typified by the greatly simplified general example ofFIGS. 1 and 2, these microscopes scan a sharp probe 10 over the surface12 of a sample 14 to obtain surface contours, in some cases actuallydown to the atomic scale. The probe 10 may be affixed to a scanningmechanism and moved in a scan pattern over the surface 12 or alternately(and equally effectively because of the small sizes involved) the probe10 may be stationary with the sample 14 mounted on a scanning mechanismthat moves the surface 12 across the probe 10 in a scanning pattern. Thetip 16 of the probe 10 rides over the surface 12 as the probe 10 ismoved across it. As the tip 16 follows the topography of the surface 12,the probe 10 moves up and down as indicated by the bi-directional arrow18. This up and down movement of the probe 10 is sensed to develop asignal which is indicative of the z directional component of the3-dimensional surface 12.

Early atomic force microscopes (AFMs) mounted the probe 10 to a wire andelectrically sensed the movement of the wire as the probe tip 16 movedover the surface 12. Recent prior art AFMs employ technology developedin the microelectronics art as depicted in FIG. 1. It should be notedthat the drawings figures herein are not to scale as the probe 10 andits tip 16 (typically of a diamond material) are extremely small so asto be useful at the near-atomic level. If the drawings were drawn toscale, these components would not be visible. In fact, when working withAFMs, these components are not visible to the naked eye and must beviewed with an optical microscope. As will be seen shortly, this is asource of some of the problems which are solved by this invention.

As depicted in FIG. 1, recent prior art AFMs have the probe 10 extendingoutward from the forward edge of a substrate 20 with the probe 10 beingformed thereat by manufacturing techniques which are not critical to thepresent invention. It is sufficient to point out that the probe 10 istypically in the form of an arm extending outward from the substrate 20with the diamond tip 16 attached at the end of the arm. Also, the probe10 is extremely small and extremely fragile. The substrate 20 istypically adhesively attached to the bottom and extending outward fromthe forward edge of a large steel block 22 mounted to the surroundingstructure. Where the probe 10 and sample 14 are conductive, the positionof the probe 10 as a result of the deflection caused by the surface 12during the scanning process can be sensed electrically. Wherenon-conductive samples are to be scanned, the prior art literaturesuggests bouncing a laser beam 24 off the probe 10 to be sensed by aphotoelectric sensor 26. As depicted in FIG. 2, as the probe 10 deflectsup and down, the reflection angle of the laser beam 24 is changed. It isthis change in reflection angle that is sensed by the photoelectricsensor 26, which then outputs an electrical signal related to the angle(by way of the beam of light striking a detecting surface), and therebythe z directional component of the probe 10.

Regardless of the probe positional sensing method employing (electricalor laser light), there are a number of problems associated with theprior art AFMs as typified by the simplified drawings of FIGS. 1 and 2.As depicted in FIG. 2, the surface 12 of a sample 14 has a thin (i.e.molecular level) coating of water 28 thereon. Often, the small,lightweight tip 16 of the probe 10 is "sucked" into the surface 12against the miniscule resilient biasing force of the probe 10 by thecapillary action of this coating of water 28. This, of course, canseriously damage the tip 16 to the point of making it non-useful for itsintended purpose. Further on the negative side, the coating of water 28is not sufficient to provide any lubricating with respect to the tip 16sliding over the surface 12. As a result, frictional wear of the tip 16is a serious problem causing the tip 16 to wear off quickly to the pointof making it non-useful of its intended purpose. Also, with some samplematerials the tip 16 may dig into and damage the sample surface 12rather than sliding over it to provide useful information. Additionally,the scanning action is accomplished by the application of fairly highvoltages to a scanning member. With the steel mounting block 22 in closeproximity as depicted in FIG. 1, these voltages can be attracted to thesteel block 22 and, in the process, affect the probe 10 therebyintroducing false data into the output stream.

The type of environment and class of persons who are and will be usingAFMs in the future also adds to the problems of this extremely usefuland potentially powerful device. Typically, the user is a researcherworking on various projects in a laboratory environment. He/she is notinterested in having to "play" with the AFM to get it to produceworkable results. In its present configuration as depicted by thedrawings of FIGS. 1 and 2, it is difficult of set up for scanning. It iseasy to break the tip 16 from the probe 10 and/or the probe 10 from thesubstrate 20. Replacing the probe/tip assembly is a major undertaking;and, because of the problems described above, the life expectancy of theprobe/tip is extremely short. Moreover, the sample 14 is glued to thetop of a piezoelectric scanning tube (not shown in FIGS. 1 or 2) whichprovides the scanning action by moving the sample with respect to thestationary probe 10 (which must remain fixed in position to have thelaser beam 24 reflect from it for detection purposes). Thus, onceplaced, the sample 14 is impossible to move (so as to change thescanning point) and difficult to change. Positioning the tip 16 of theprobe 10 on the surface 12 of the sample 14 is difficult at best andvirtually impossible in some cases. In short, while AFMs are moving intoa commercial stage of development, the products which are available inthe prior art are not the efficient, easy to use laboratory aids thatthe users thereof desire and need.

Wherefore, it is an object of the present invention to provide an AFMsystem which is easy to set up, calibrate, and use in the typicallaboratory environment by the typical laboratory worker.

It is another object of the present invention to provide an AFM systemin which the probe/tip resist frictional wear.

It is still another object of the present invention to provide an AFMsystem in which the probe/tip are not subjected to the capillary forcesof water coating the surface of the sample.

It is yet another object of the present .[.inventio.]. .Iadd.invention.Iaddend.to provide an AFM system in which the probe/tip slide easilyover the sample surface and resist digging into softer samples anddamaging them thereby providing a gentler and more reliable operation.

It is a further object of the present invention to provide an AFM systemin which the probe/tip are contained in an easily replaceable modulewhich is recyclable by the AFM supplier.

It is a still further object of the present invention to provide an AFMsystem having calibration/setup tools included therewith which make thesetting up of the AFM a simple and straightforward task.

It is another object of the present invention to provide an AFM systemin which the sample is held by a removeable and adjustable member whichallows the position of the sample to be changed in situ and allows a newsample to be installed easily and quickly without destruction ofprevious samples.

It is also an object of the present invention to provide an AFM systemin which the steel mounting block of the prior art is removed withoutaffecting the stability of the probe and tip.

Other objects and benefits of this invention will become apparent fromthe description which follows hereinafter when taken in conjunction withthe drawing figures which accompany it.

SUMMARY

The foregoing objects have been achieved in the atomic force microscopeof the present invention which is quickly and easily set up and in whichthe probe thereof is easily replaceable and resists breakage duringsetup comprising, a horizontal base member; a scan tube verticallysupported at a bottom end by the base member and having a top surfacefor holding a sample to be scanned and moveable in x-, y-, andz-directions as a result of scanning voltages applied thereto; firstsupport means extending upward from the base member; a sample holdingblock having a chamber therein; the sample holding block having a firstbore communicating with the chamber through a bottom surface, a secondbore communicating with the chamber through a top surface, and a thirdbore communicating with the chamber at an acute angle to the secondbore, the sample holding block being positioned with the scan tubepassing through the first bore and supported by the first support means;second support means extending upward from the bottom surface into thechamber; a probe-carrying module having parallel top and bottom surfacesremovably disposed in the chamber and supported by the second supportmeans, the bottom surface having a probe attached thereto and extendingdownward therefrom at an acute angle with respect to the bottom surfaceof the probe-carrying module and with a tip of the probe positioned tocontact a sample mounted on the top surface of the scan tube; a sourceof a laser beam mounted for directing the laser beam down the secondbore from the top surface of the sample holding block to pass throughthe probe-carrying module, strike the probe, and be reflected backthrough the probe-carrying module and down the third bore to an outerend thereof; and, photoelectric sensor means having an active surfacepositioned over the outer end of the third bore for developing anelectrical signal at an output thereof reflecting the position on theactive surface at which the laser beam strikes the active surface.

In one embodiment, the probe-carrying module is of an opticallytransparent material whereby the laser beam can pass through theprobe-carrying module, strike the probe, and be reflected back throughthe probe-carrying module. In another embodiment, the probe-carryingmodule is of an optically non-transparent material and has alaser-passing bore therethrough between the top and bottom surfacesaligned so that the laser beam can pass through the laser-passing bore,strike the probe, and be reflected back through the laser-passing bore.

In the preferred embodiment, the probe-carrying module includes anangled pad on the bottom surface thereof and the probe carried by theprobe-carrying module comprises a substrate attached to the pad and apair of arms of a smooth-surfaced, minimally self-biased materialcantilevered outward from a bottom front edge of the substrate in aV-shape to form an optical lever, the pair of arms having a probe pointat the apex of the V-shape thereof.

In the preferred embodiment, the first support means comprises threefirst adjusting screws threaded through the base member with the sampleholding block resting on top ends thereof with one of the top endsdisposed in a slot in a flat bottom surface of the sample holding back,another of the top ends disposed in a hole in the bottom surface, and athird of the top ends disposed on the bottom surface whereby the sampleholding block is removable from the base member and repeatedlyreplaceable to a pre-established position thereon. Additionally, thesecond support means comprises three second adjusting screws threadedthrough the bottom surface of the sample holding block with theprobe-carrying module resting on top ends thereof with one of the topends disposed in a slot in a flat bottom surface of the probe-carryingmodule, another of the top ends disposed in a hole in a member affixedto the bottom surface, and a third of the top ends disposed on thebottom surface whereby the probe-carrying module is removable from thechamber of the sample holding block and repeatedly replaceable to apre-established position therein.

The preferred fluid cell is .[.prvivded.]. .Iadd.provided .Iaddend.bythe probe-carrying module being of an optically transparent material andadditional sealing means surrounding the probe and attached to thebottom surface of the probe-carrying module or sealing to a top surfaceof a sample to form a fluid cell around the probe. The preferred fluidcell includes an inlet bore and an outlet bore in the probe-carryingmodule communicating between the fluid cell and the exterior of theprobe-carrying module whereby fluid can be inserted into the fluid cell.

Preferably, there is an electrode bore in the probe-carrying modulecommunicating between the fluid cell and the exterior of theprobe-carrying module and an electrode disposed in the electrode borehaving a first end within the fluid cell and a second end at theexterior of the probe-carrying module to which electrical connection canbe made. For electro-chemical use, there are three electrode bores inthe probe-carrying module communicating between the fluid cell and theexterior of the probe-carrying module as well as a working electrode, areference electrode, and an auxiliary electrode disposed in theelectrode bores, each of the electrodes having a first end within thefluid cell and a second end at the exterior of the probe-carrying moduleto which electrical connection can be made.

Preferred operation is achieved by including a voltage shield of anelectrically conductive material disposed over the top surface of thescan tube in non-electrical contact therewith, the voltage shield beingelectrically connected to a fixed voltage source whereby to shield theprobe from the effects of the scanning voltages applied to the scantube.

To provide ease of sample placement, replacement, and lateraladjustment, there is a slidably moveable and removeable stage releasablyattached to the top surface of the scan tube for releasably andadjustably holding a sample to be scanned attached thereto. In oneembodiment, the stage contains a magnet therein and the voltage shieldis of a ferro-magnetic material to which the stage can magneticallyattach and upon which it can slide. In another embodiment, the stage isof a ferro-magnetic material and the voltage shield contains the magnettherein.

The preferred system includes various calibration means to make a user'sjob one of microscope use and not one of detailed setup and maintenance.In particular, there are first calibration means for positioning themember affixed to the bottom surface of the probe-carrying module as afunction of the position of a tip portion of the probe; secondcalibration means for setting the position of the sample holding blockon the first support means; and, third calibration means for setting theposition of the probe-carrying module on the second support means.

DESCRIPTION OF THE DRAWINGS:

FIG. 1 is a simplified drawing of a prior art atomic force microscopeshowing the probe as mounted to a substrate carried by a large steelblock being detected by a laser beam being reflected therefrom.

FIG. 2 is an enlarged drawing of the tip of the probe of FIG. 1 showingthe movement of the tip over the surface of a sample and how thereflection angle of the laser beam is changed as a result of deflectionof the probe.

FIG. 3 is a partially cutaway side view of an atomic force microscopeaccording to the present invention.

FIG. 4 is an enlarged cutaway side view of the sample-holding block ofthe atomic force microscope of FIG. 3 showing how the supporting screwsthereof are calibrated to a proper height.

FIG. 5 is an enlarged cutaway side view of the sample-holding block ofFIG. 4 mounted on the base portion of the atomic force microscope ofFIG. 3 showing how the supporting screws thereof are calibrated to placethe probe tip at a proper height.

FIG. 6 is an enlarged cutaway side view of the probe and tip of anon-preferred embodiment of the present invention in which the scanningtakes place within a fluid drop.

FIG. 7 is a bottom view of the probe-carrying module of the presentinvention in its preferred embodiment.

FIG. 8 is a cutaway view of the probe-carrying module of FIG. 7 in theplane VIII--VIII.

FIG. 9 is a simplified drawing depicting a prior art three pointsupport/adjustment technique as employed in the present invention.

FIG. 10 is a side view of a calibration tool employed in the AFM systemof the present invention to make the probe-carrying module position theprobe tip exactly in its proper position when the probe-carrying moduleis inserted into the sample-holding block of FIG. 4.

FIG. 11 is a bottom view of the calibration tool of FIG. 10.

FIG. 12 is a drawing depicting the use of the calibration tool of FIGS.10 and 11.

FIG. 13 is a partially cutaway side view of the top of a piezoelectricscanning tube employing the voltage shield and the removable/slideablestage of the present invention in a first embodiment.

FIG. 14 is a detailed drawing of the preferred holding and adjustingmechanism for the photoelectric sensor employed in the presentinvention.

FIG. 15 is a partially cutaway side view of the top of a piezoelectricscanning tube employing the voltage shield and the removable/slideablestage of the present invention in an alternate embodiment.

FIG. 16 is a top view of the preferred probe configuration of thepresent invention.

FIG. 17 is a front view of the probe of FIG. 16.

FIG. 18 is a drawing of an optional removeable but non-transparentprobe-carrying module without fluid cell potential that may be employedin the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT:

The essential elements of an AFM 28 according to the present inventionin its preferred embodiment are depicted in the cutaway side view ofFIG. 3. There is a base 30 which, as in the typical prior art AFM, isshock mounted in some manner. A piezoelectric scan tube 32 is mountedextending perpendicularly upward from the base 30. The scan tube 32 isof a conventional design well known in the art whereby by theapplication of .[.z-.]. .Iadd.x-.Iaddend., y-, and z-directional scanvoltages to the wires 34, the top end 36 of the tube 32 can be movedhorizontally in two orthogonal directions and vertically to provide xand y scanning as well as fine probe positioning in the z direction tothe atomic level.

A sample-holding block 38 is supported on the tips of three adjustingscrews 40 threaded through the base 30 employing a hole/slot/surfacecontact and alignment technique which is well known in the art, to beaddressed in greater detail later herein. As can be seen, the scan tube32 extends through a bore 42 in the bottom 44 of the sample-holdingblock 38 so that the top end 36 thereof is within a chamber 46 withinthe sample-holding block 38. A probe-carrying module 48 is disposedwithin the chamber 46 and supported on the tips of three adjustingscrews 50 threaded through the bottom 44 employing a special applicationof the above-mentioned hole/slot/surface contact and alignmenttechnique, which will also be addressed in greater detail later herein.The probe-carrying .[.moduel.]. .Iadd.module .Iaddend.48, as will beseen shortly, provides the solution to several major problems of priorart AFMs as described above. The probe-carrying module 48 is of atransparent material having parallel, planar top and bottom surfaces,52, 54, respectively. In order of preference, the probe-carrying module48 can be made of quartz, glass, or a plastic such as polycarbonate. Thesubstrate 20 having the probe 10 mounted thereto is glued to the bottomsurface 54 within an O-ring 56 also glued to the bottom surface 54. Aswill be described in further detail shortly, this arrangement can beemployed to place the probe 10 within a fluid cell which can existbetween the bottom surface 54 and the sample 14 within the O-ring 56.That, of course, eliminates the capillary attraction problem describedabove and provides a low friction/lubricating environment wherein evensoft tissue samples, and the like, can be scanned without damagethereto. As will be noted, the steel block 22 of the prior art has beeneliminated, as desired. The probe tip 16 is automatically aligned withrespect to the laser beam 24 in a manner to be described shortly.Perhaps most important, the probe-carrying module 48 can be removed andreplaced quickly, accurately, and easily if and when the probe/tipbecome broken and/or worn. The used module 48 can then be returned tothe factory for the installation of a new probe 10 under the properconditions. The sample 14 is attached to the top of a removable samplestage 58. Thus, a particular sample 14 can be attached easily to thestage 58 at a bench location away from the AFM 28. If desired, aparticular sample can be removed temporarily and then be reinserted at alater time. Additionally, the sample stage 58 is magnetically attachedto a ferromagnetic electrical interference shield 60 carried by the topend 36 of the scan tube 32. The shield 60 prevents electricalinterference from the scan voltages applied to the tube 32 and,additionally, the magnetic attachment of the sample stage 58 theretopermits the stage 58 (and attached sample 14) to be slid horizontally inthe x and y directions to place the desired area for scanning under theprobe tip 16.

The top of the sample holding block 38 has a flat stage area 62 thereonwhich is parallel to the bottom 44. A bore 64 extends perpendicularlyfrom the stage area 62 into the chamber 46 generally concentricallyabout a point on the probe-carrying module 48 where the tip 16 of theprobe 10 is to be located. A laser beam source 66 is carried by arectangular holding member 68 magnetically attached to the stage area 62for horizontal sliding movement thereon. The laser beam 24 from thesource 66, therefore, shines down the bore 64 to strike the probe 10from whence it is angularly reflected up bore 70 to strike the detectingsurface 72 of a photoelectric sensor 26 (of a type well known in the artwhich individually forms no part of the novelty of this invention). Thesensor 26 is adjustably held in a micro detector adjustor 74. Inpresently tested embodiments of this invention, the source 66 of thelaser beam 24 is a holder gripping one end of an optic fiber which hasthe laser beam 24 from a commercial laser device input thereto at theopposite end to prevent heat buildup from the laser device in the areaof the probe 10 and associated apparatus. A preferred source 66 wouldinclude a laser-emitting diode located within the source 66 itself. Thehorizontal position of the holding member 68 is fine-adjusted in the xand y directions (to place the laser beam 24 exactly on the probe 10 foroptimum reflection) by means of a pair of orthogonally oriented microlaser adjustors 76. Having thus described the present invention and itsvarious components and aspects in a general manner, the various point ofnovelty will now be addressed in greater detail.

The sample holding block 38 and the method of setting the adjustingscrews 50 is depicted in the enlarged drawing of FIG. 4. As can be seenfrom this figure, there are micro laser adjustors 76 oriented at 90° toone another. Each adjustor 76 comprises a vertical member 78 extendingupward from the sample holding block 38 adjacent the stage area 62. Aleaf spring member 80 extends upward along the inner surface of thevertical member 78 from a point of attachment thereto at 82. A magneticprobe 84 extends outward towards the stage area 62 from a point justabove the point of attachment 82. An adjusting screw 86 is threadedthrough the vertical member 78 into contact with the leaf spring member80 near the top of the vertical member 78. Note that the adjustingscrews 86 have a large diameter turning wheel 88 on the outer endthereof whereby the adjusting screws 86 .[.cna.]. .Iadd.can .Iaddend.beturned easily a fraction of a rotation when horizontally adjusting theposition of the holding member 68 on the stage area 62. Note also thatthere is a large mechanical advantage from the positioning of theadjusting screw 86 on the leaf spring member 80 with respect to themagnetic probe 84 and the point of attachment 82. As a result, turningthe wheel 88 (which can be accomplished easily and smoothly because ofthe mechanical advantages provided) will result in a very smallhorizontal movement of the holding member 68, which is desirable inorder to be able to accurately accomplish the final positioning of thelaser beam 24 on the probe 10.

As depicted in detail in FIG. 14, the preferred micro detector adjustor74 comprises a U-shaped slider member 90 magnetically adhering to thesliding surface 92 of the sample holding block 38, which isperpendicular to the bore 70. The sensor 26 is held within thesideward-facing U of the slider member 90 by a holder 148 having an area150 therein sized to the contours of the sensor 26. Both the holder 148and the slider member 90 are held to the sliding surface 92 by magnets116. The slider member 90 is moved up and down by the adjusting screw 94which is threaded through the slider member 90 between the webs 96 inthe sample holding block 38 provided for the purpose. The holder 148 ismoved sideways by the adjusting screw 152 threaded through the bottom ofthe U of the slider member 90.

The position of the adjusting screws 50 (and thereby the position of theprobe-carrying module 48 when inserted into the chamber 46) can be setusing a calibration blank 98 and height gauge 100 as shown. The heightgauge 100 is inserted into the bore 42 and the calibration blank 98 ispositioned on the adjusting screws 50. The screws 50 are then raisedand/or lowered, as appropriate, until the calibration blank 98 is justresting evenly on the flat top surface of the height gauge 100. At thatpoint, the screws 50 are set to a height such that when theprobe-carrying module 48 is positioned on the screws, the probe tip 16will be at the desired (and anticipated) probe height as shown.

The adjusting screws 40 must also be set to a proper height to supportthe probe-carrying module 48 at a point where the sample surface of amounted sample to be scanned will be at the probe level anticipated bythe calibration procedure just described with respect to FIG. 4. This isaccomplished using the calibration tool 102 in the manner depicted inFIG. 5. Calibration tool 102 comprises a yoke 104 having a bottom 106configured exactly like the bottom 44 of the sample holding block 38,including a bore 42' for the scan tube 32 to pass through. It should benoted that, as will be seen from a description contained hereinafter,while the adjusting screws 50 of the sample holding block 38 need beadjusted only rarely, the adjusting screws 40 will need to be adjustedwhenever the sample 14 is changed. This is because the sample 14 isglued to the sample stage 58 and the height of the sample surface maychange significantly from one sample to the next, at least in the sizesbeing considered in the operation of the AFM 28. The calibration tool102 also has a short focal length calibration microscope 108 positionedperpendicularly to be above the sample surface 12 when the calibrationtool 102 is mounted on the adjusting screws 40. The focal length of thecalibration microscope 108 is chosen such as to focus exactly at theplane the probe tip 16 will be in. To properly adjust the adjustingscrews 40, the sample 14 is mounted on the scan tube 20 and thecalibration tool 102 positioned as shown in FIG. 5. While viewingthrough the calibration microscope 102, the adjusting screws 40 are usedto move the calibration tool 102 up and down until the entire surface 12of the sample 14 is in focus. At that point, the adjusting screws 40 areproperly set. Because of the short focal length employed, the surface12, when completely in focus, is also parallel to the scanning action ofthe probe 10.

Before continuing with the setup and calibration aspects of the presentinvention, attention is directed to FIGS. 13 and 15 which are directlyrelated to the last described aspects of this invention. As mentionedearlier, the scanning movement of the piezoelectric scan tube 32 isaffected by the application of voltages (which can be in the 100 voltrange) to electrodes 110 on the exterior and interior surfaces of thetube 32, which is made of a piezoelectric material. Independently of theattracting potential of the steel block 22 (which has been removed inthe preferred embodiment of this invention), the inventors herein haveobserved (and proved) that the scanning voltages employed to move thescan tube 32 can still adversely affect the probe 10. To solve thisproblem, a disk shaped voltage shield 112 is attached to the top end 36of the tube 32. Since the shield 112 must be electrically conductive, itis attached to the top end 36 of the tube 32 with an insulating adhesive114. The voltage shield 112 is then physically connected to a groundpotential. Optionally, it can be connected to a fixed voltage potentialwhich is available.

The adjustability and removability aspects of the sample stage 58 can beaccomplished in two ways as depicted in FIGS. 13 and 15, respectively.In the embodiment of FIG. 13, the voltage shield 112 is of aferro-magnetic material and the sample stage 58 has a magnet 116 mountedtherein. In the embodiment of FIG. 15, the voltage shield 112 has amagnet 116 mounted concentrically therein and the sample stage 58 is ofa ferro-magnetic material. Accordingly, in either embodiment the voltageshield 112 not only shields against the effects of stray voltagesreaching the probe 10; but, additionally, provides a surface on the topend 36 of the scan tube 32 onto which the removeable sample stage 58having a sample 14 glued thereto can be magnetically attached.Accordingly, while the sample 14 is positioned on the tube 32 and aspart of the adjustment of the adjusting screws 40 as described withrespect to FIG. 5, the sample stage 58 can be slid horizontally in boththe x and y directions to place an area of interest under the probe tobe scanned thereby.

The problems of capillary action and friction in soft samples as well asthe providing of the gentler and more reliable operation will now beaddressed. An important aspect of the AFM 28 of this invention is theinclusion of a unique probe design which is, in fact, a microfabricatedcantilever with an optical lever as shown in FIGS. 16 and 17. The probe10 comprises a pair of V-shaped arms 154 formed on the bottom forwardedge of the supporting substrate 20 by microfabrication techniques wellknown in the microelectronics art which, per se, form no part of thisinvention. The arms 154 are, therefore, cantilevered out from the bottomforward edge of the substrate 20. Because of the nature of the materialsemployed in such microfabrication, the cantilevered arms 154 deflecteasily (i.e. their self biasing force is practically non-existent).Because such microfabricated materials have a very smooth surface, theinherently reflect the laser beam 24, thus forming the desired opticallever. The actual contacting tip 16 is made of diamond and separatelyattached where the two arms 154 join to form the "V".

The problems of capillary action and friction in soft samples can besolved in the AFM 28 of this invention by optionally having the probe 10and area of the sample being scanned immersed in a fluid bath. In anon-preferred embodiment, this novel aspect of the present invention canbe accomplished in the manner shown in FIG. 6. This approach wasemployed in early tested embodiments of the present invention; but, hasbeen superceded by the apparatus to be described shortly. As will benoted, this embodiment employs the prior art technique of having theprobe 10 mounted on a substrate 20 which, in turn, is mounted to a steelblock 22, or the like, carried by the base portion of the AFM. Toprovide the fluid bath, a clear cover glass 118 is attached to the topof the substrate 20 extending outward over the probe 10. A drop of fluid120 (such as de-ionized water) is then injected with a syringe into thearea surrounding the probe 10 defined by the cover glass 118, the samplesurface 12, and the edge of the substrate 20, where it adheres bycapillary action and surface tension. The laser beam 24 passes throughthe cover glass 118 and fluid 120 to the probe 10 from which it isreflected to pass back through the fluid 120 and cover glass 118. Anyminor refraction will remain constant and can be accounted for byadjusting the position of the photoelectric sensor 26. Other than beingassociated with the non-replaceable, steel block mounted probe 10, theonly other problem with this embodiment is that the life of the drop offluid 120 is limited due to evaporation.

The probe-carrying module 48 .[.shwon.]. .Iadd.shown .Iaddend.in detailin FIGS. 7 and 8 solves many of the problems associated with the priorart while, when desired or needed, optionally providing the novel fluidcell environment of this invention and is, therefore, the preferredapproach. Each probe-carrying module 48 is assembled and calibrated (inthe manner to be described shortly) at the factory. As mentionedearlier, if the probe 10 wears out or breaks off, the researcher merelyinstalls a new probe-carrying module 48 and sends the broken one back tothe factory for recycling. The probe-carrying module 48 has an angledarea 122 (approximately 10°) cut into the bottom surface 54 into whichthe probe carrying substrate 20 is glued. The probe 10 and substrate 20are surrounded by an O-ring 56 which is also adhesively attached to thebottom surface 54. When the O-ring 56 is positioned on the surface 12 ofthe sample 10 as shown in FIG. 8, a fluid cell 124 is formed between thebottom surface 54 and the sample surface 12 within the O-ring 56. Inletand outlet tubes 126, 128 are formed into the material of theprobe-carrying module 48 communicating with the fluid cell 124 and theexterior of the module 48. Fluid 120 can be injected (or even circulatedif applicable) through the tubes 126, 128. The evaporation problem is,therefore, eliminated. It should be noted that where the fluid cell isnot needed, the optional probe-carrying module 48 of FIG. 18 can beemployed. In this case, the probe-carrying module 48' is of metal orplastic and, as with the above-described version, has an angled area 122(approximately 10°) cut into the bottom surface 54 into which the probecarrying substrate 20 is glued. A bore 156 through the probe-carryingmodule 48' from the top surface 52 to the bottom surface 54 aligned withthe probe 10 is provided to allow the laser beam 24 to pass through theprobe-carrying module 48', strike the probe 10, and be reflectedtherefrom to the photoelectric sensor 26.

Returning to the above-described preferred probe-carrying module 48containing the fluid cell, in addition to providing the benefitsdescribed with respect to eliminating the capillary attraction affect onthe probe 10 and the reduction of friction in soft samples, the fluidcell can also be employed for electro-chemical purposes, and the like.To this end, in the preferred embodiment of this invention threeadditional tubes 158, 160, and 162 are formed into the material of theprobe-carrying module 48 communicating with the fluid cell 124 and theexterior of the module 48. Each of the tubes contains an electrode 164extending between the fluid cell 124 on one end and the exterior of themodule 48 on the other, at which point electrical connection can be madethereto. As will readily be appreciated by those skilled in the art,such an arrangement has many uses. For example, samples could be "pinneddown" to substrates electrically by applying a voltage between one ormore of the electrodes 164 in the fluid cell (containing the sample) andthe voltage shield 112. The presence of the three electrodes 164 (i.e. aworking electrode, a reference electrode, and an auxiliary electrode)make possible a wide range of electro-chemical studies such as plating,corrosion, and electrostripping within the real-time environment of theAFM 28.

The prior art hole/slot/support system employed in the invention andmentioned earlier is depicted in simplified form in FIG. 9. Threepoints, of course, define a plane as is a well known mathematical factjust as the fact that two points define a straight line. A simplerexample is the three legged stool, which will never wobble like its fourlegged cousin. Thus, in complex apparatus such as the AFM 28 whereinstability of the components therein with respect to one another, the useof a three point support system is a logical approach. To provideaccuracy of placement with adjustability, the hole/slot/supporttechnique of FIG. 9 is commonly employed. The surface to be supportedhas a straight slot 130 formed therein at a first general point ofsupport. A hole 132 is formed into the surface in longitudinal alignmentwith the slot 130 at a second, but specific, point of support. Thesurface to be supported is placed on three supports by first placing onesupport into the slot 130. The one support is then slid within the slotas required and the article rotated as needed to allow a second of thethree supports to be inserted into the hole 132. Two points of supporthave thus been established. As two points define a line, the two supportpoints only allow rotation of the surface to be supported about thesupport points in the hole 132 and slot 130. The surface to be supportedis then lower (i.e. rotated about the line defined by the first twosupport points) until the surface to be supported is resting on thethird of the three supports. This supporting technique will repeatedlyresult in the same positioning of the surface to be supported on thethree supports.

While the above-described prior art three point support system is usedthroughout the AFM 28, a novel approach thereto is used to pre-calibratethe probe-carrying modules 48 at the factory so that when one isinserted into the chamber 46 to be supported by the adjusting screws 50,the probe tip 16 will be placed in approximate accurate alignment withthe nominal position of the laser beam 24. As can be seen from thedrawing of FIG. 7 the bottom surface 54 of the probe-carrying module 48has only a slot 130 formed therein. The "hole" 132 is provided accordingto the calibration technique shown in FIGS. 10-12. At the factory, afterthe substrate 20 with the probe 10 attached is affixed to the angledarea 122, the calibration tool 134 of FIGS. 10 and 11 is employed toposition a washer 136 so that the hole in the center of the washer 136is the hole 132' which receives the second of the adjusting screws 50.The calibration tool 134 has a horizontal base 138 with three pins 140extending downward therefrom perpendicular to the base 138 and spaced inthe same triangular shape as the three adjusting screws 50. A microscope142 is vertically fit into a bore 144 through the base 138 which has thesame relationship to the pins 140 that the bore 64 has to the adjustingscrews 50. Crosshairs 146 within the microscope 142 cross in theapproximate position of the laser beam 24 within the bore 64. With theprobe-carrying module 48 lying on its top surface 52, one pin 140 isinserted in the slot 130. A washer 136 is placed on the bottom surface54 and another of the pins 140 is inserted into the hole 132' thereofand then placed on the bottom surface 54 along with the third pin 140.The calibration tool 134 is then slid over the bottom surface 54 toplace the probe tip 16 in the center of the crosshairs 146. The washer136 is then glued to the bottom surface 54 by the application of afast-drying glue thereof such as that sold under the trademarkKrazy-Glue. That completes the calibration procedure as the hole 132' isnow fixed so as to place the probe tip 16 in the proper position whenthe probe-carrying module 48 is used in an AFM 28. After insertion ofthe probe-carrying module 48 into the chamber 46, the micro laseradjustors 76 are then used to precisely place the laser beam 24 on theprobe 10 for optimum reflection. Simultaneously, the micro detectoradjustor 76 is used to optimally position the photoelectric sensor 26.Thus, the AFM 28 of this invention can be placed into service for usefulwork quickly and easily without undue expense of time and without theneed for a high degree of technical training. If the procedures as setforth above are followed, the probe 10 is virtually unbreakable as aresult of the setup procedure; and, when the probe 10 does wear out orbreak, it is quickly and easily replaced.

Wherefore, having thus described our invention, what is claimed is: 1.An atomic force microscope which is quickly and easily set up and inwhich the probe thereof is easily replaceable and resists breakageduring setup comprising:(a) a horizontal base member; (b) a scan tubevertically supported at a bottom end by said base member and having atop surface for holding a sample to be scanned and moveable in x-, y-,and z-directions as a result of scanning voltages applied thereto; (c)first support means extending upward from said base member; (d) a sampleholding block having a chamber therein, said sample holding block havinga first bore communicating with said chamber through a bottom surface, asecond bore communicating with said chamber through a top surface, and athird bore communicating with said chamber at an acute angle to saidsecond bore, said sample holding block being positioned with said scantube passing through said first bore and supported by said first supportmeans; (e) second support means extending upward from said bottomsurface into said chamber; (f) a probe-carrying module having top andbottom surfaces removably disposed in said chamber and supported by saidsecond support means, said bottom surface having a probe attachedthereto and extending downward therefrom at an acute angle with respectto said bottom surface of said probe-carrying module and with a tip ofsaid probe positioned to contact a sample mounted on said top surface ofsaid scan tube; (g) a source of a laser beam mounted for directing saidlaser beam down said second bore from said top surface of said sampleholding block to pass through said probe-carrying module, strike saidprobe, and be reflected back through said probe-carrying module and downsaid third bore to an outer end thereof; and, (h) photoelectric sensormeans having an active surface positioned over said outer end of saidthird bore for developing an electrical signal at an output thereofreflecting the position on said active surface at which said laser beamstrikes said active surface.
 2. The atomic force microscope of claim 1wherein:said probe-carrying module is of an optically transparentmaterial whereby said laser beam can pass through said probe-carryingmodule, strike said probe, and be reflected back through saidprobe-carrying module.
 3. The atomic force microscope of claim 1wherein:said probe-carrying module is of an optically non-transparentmaterial and has a laser-passing bore therethrough between said top andbottom surfaces aligned so that said laser beam can pas through saidlaser-passing bore, strike said probe, and be reflected back throughsaid laser-passing bore.
 4. The atomic force microscope of claim 1wherein said probe-carrying module includes an angled pad on said bottomsurface thereof and said probe carried by said probe-carrying modulecomprises;(a) a substrate attached to said pad; and, (b) and arm of asmooth-surfaced, minimally self-biased material cantilevered outwardfrom a bottom front edge of said substrate to form an optical lever,said arm having a probe point at an outer end thereof.
 5. The atomicforce microscope of claim 1 wherein:said first support means comprisesthree first adjusting screws threaded through said base member with saidsample holding block resting on top ends thereof with one of said topends disposed in a slot in a flat bottom surface of said sample holdingblock, another of said top ends disposed in a hole in said bottomsurface, and a third of said top ends disposed on said bottom surfacewhereby said sample holding block is removable from said base member andrepeatably replaceable to a pre-established position thereon.
 6. Theatomic microscope of claim 1 wherein:said second support means comprisesthree second adjusting screws threaded through said bottom surface ofsaid sample holding block with said probe-carrying module resting on topends thereof with one of said top ends disposed in a slot in a flatbottom surface of said probe-carrying module, another of said top endsdisposed in a hole in a member affixed to said bottom surface, and athird of said top ends disposed on said bottom surface whereby saidprobe-carrying module is removable from said chamber of said sampleholding block and repeatedly replaceable to a pre-established positiontherein.
 7. The atomic force microscope of claim 1 wherein saidprobe-carrying module is of an optically transparent material andadditionally comprising:sealing means surrounding said probe andattached to said bottom surface of said probe-carrying module forsealing to a top surface of a sample to form a fluid cell around saidprobe.
 8. The atomic force microscope of claim 7 and additionallycomprising:an inlet bore and an outlet bore in said probe-carryingmodule communicating between said fluid cell and the exterior of saidprobe-carrying module whereby fluid can be inserted into said fluidcell.
 9. The atomic force microscope of claim 7 and additionallycomprising:(a) an electrode bore in said probe-carrying modulecommunicating between said fluid cell and the exterior of saidprobe-carrying module; and, (b) an electrode disposed in said electrodebore having a first end within said fluid cell and a second end at theexterior of said probe-carrying module to which electrical connectioncan be made.
 10. The atomic force microscope of claim 7 and additionallycomprising:(a) three electrode bores in said probe-carrying modulecommunicating between said fluid cell and the exterior of saidprobe-carrying module; and, (b) a working electrode, a referenceelectrode, and an auxiliary electrode disposed in said electrode bores,each of said electrodes having a first end within said fluid cell and asecond end at the exterior of said probe-carrying module to whichelectrical connection can be made.
 11. The atomic force microscope ofclaim 1 and additionally comprising:a voltage shield of an electricallyconductive material disposed over said top surface of said scan tube innon-electrical contact therewith, said voltage shield being electricallyconnected to a fixed voltage source whereby to shield said probe fromthe effects of said scanning voltages applied to said scan tube.
 12. Theatomic force microscope of claim 11 wherein:said fixed voltage source isground.
 13. The atomic force microscope of claim 1 and additionallycomprising:a slidably moveable and removeable stage releasably attachedto said top surface of said scan tube for releasably and adjustablyholding a sample to be scanned attached thereto.
 14. The atomci forcemicroscope of claim 13 wherein:(a) said stage contains a magnet therein;and additionally comprising, (b) a voltage shield of a ferro-magneticand electrically conductive material disposed over said top surface ofsaid scan tube in non-electrical contact therewith, said voltage shieldbeing electrically connected to a fixed voltage source to shield saidprobe from the effects of said scanning voltages applied to said scantube and providing an attachment surface to which said stage canmagnetically attach and upon which it can slide.
 15. The atomic forcemicroscope of claim 13 wherein:(a) said stage is of a ferro-magneticmaterial; and additionally comprising, (b) a voltage shield of anelectrically conductive material disposed over said top surface of saidscan tube in non-electrical contact therewith, said voltage shieldcontaining a magnet therein, being electrically connected to a fixedvoltage source to shield said probe from the effects of said scanningvoltages applied to said scan tube, and providing an attachment surfaceto which said stage can magnetically attach and upon which it can slide.16. The atomic force microscope of claim 6 and additionallycomprising:first calibration means for positioning said member affixedto said bottom surface of said probe-carrying module as a function ofthe position of a tip portion of said probe.
 17. The atomic forcemicroscope of claim 1 and additionally comprising:second calibrationmeans for setting the position of said sample holding block on saidfirst support means.
 18. The atomic force microscope of claim 1 andadditionally comprising:third calibration means for setting the positionof said probe-carrying module on said second support means.
 19. Anatomic force microscope having extended use capabilities comprising:(a)a horizontal base member; (b) a scan tube vertically supported at abottom end by said base member and having a top surface for holding asample to be scanned and moveable in x-, y-, and z-directions as aresult of scanning voltages applied thereto; (c) first support meansextending upward from said base member; (d) a sample holding blockhaving a chamber therein, said sample holding block having a first borecommunicating with said chamber through a bottom surface, a second borecommunicating with said chamber through a top surface, and a third borecommunicating with said chamber at an acute angle to said second bore,said sample holding block being positioned with said scan tube passingthrough said first bore and supported by said first support means; (e)second support means extending upward from said bottom surface into saidchamber; (f) a probe-carrying module having a probe attached thereto andextending downward therefrom at an acute angle with a tip of said probepositioned to contact a sample mounted on said top surface of said scantube, said probe carried by said probe-carrying module comprising asubstrate attached to said probe-carrying module and an arm of asmooth-surfaced, minimally self-biased material cantilevered outwardfrom a bottom front edge of said substrate to form an optical lever,said arm having a probe point at an outer end thereof; (g) a source of alaser beam mounted for directing said laser beam down said second borefrom said top surface of said sample holding block to strike said probeand be reflected down said third bore to an outer end thereof; and, (h)photoelectric sensor means having an active surface positioned over saidouter end of said third bore for developing an electrical signal at anoutput thereof reflecting the position on said active surface at whichsaid laser beam strikes said active surface.
 20. The atomic forcemicroscope of claim 19 wherein:said probe-carrying module has top andbottom surfaces and is removably disposed in said chambeer and supportedby said second support means, said bottom surface having said probeattached thereto and extending downward therefrom at an acute angle withrespect to said bottom surface of said probe-carrying module and withsaid tip of said probe positioned to contact a sample mounted on saidtop surface of said scan tube whereby said laser beam passes throughsaid probe-carrying module, strikes said probe, and is reflected backthrough said probe-carrying module and down said third bore to saidouter end thereof.
 21. The atomic force microscope of claim 20wherein:said probe-carrying module is an optically transparent materialwhereby said laser beam can pass through said probe-carrying module,strike said probe, and be reflected back through said probe-carryingmodule.
 22. The atomic force microscope of claim 20 wherein:saidprobe-carrying module is of an optically non-transparent material andhas a laser-passing bore therethrough between said top and bottomsurfaces aligned so that said laser beam can pass through saidlaser-passing bore, strike said probe, and be reflected back throughsaid laser-passing bore.
 23. The atomic force microscope of claim 19wherein:said first support means comprises three first adjusting screwsthreaded through said base member with said sample holding block restingon top ends thereof with one of said top ends disposed in a slot in aflat bottom surface of said sample holding block, another of said topends disposed in a hole in said bottom surface, and a third of said topends disposed on said bottom surface whereby said sample holding blockis removable from said base member and repeatedly replaceable to apre-established position thereon.
 24. The atomic force microscope ofclaim 19 wherein:said second support means comprises three secondadjusting screws threaded through said bottom surface of said sampleholding block with said probe-carrying module resting on top endsthereof with one of said top ends disposed in a slot in a flat bottomsurface of said probe-carrying module, another of said top ends disposedin a hole in a member affixed to said bottom surface, and a third ofsaid top ends disposed on said bottom surface whereby saidprobe-carrying module is removable from said chamber of said sampleholding block and repeatedly replaceable to a pre-established positiontherein.
 25. The atomic force microscope of claim 19 and additionallycomprising:means for forming a fluid cell around said probe.
 26. Theatomic force microscope of claim 25 wherein said means for forming afluid cell around said probe comprises:a cover plate of an opticallytransparent material disposed over said probe whereby a drop of fluidcan be held between said cover plate and a top surface of a sample bycapillary action whereby said laser beam can pass through said coverplate, strike said probe, and be reflected back through said coverplate.
 27. The atomic force microscope of claim 25 wherein saidprobe-carrying module is of an optically transparent material and saidmeans for forming a fluid cell around said probe comprises:sealing meanssurrounding said probe and attached to said bottom surface of saidprobe-carrying module for sealing to a top surface of a sample to form afluid cell around said probe.
 28. The atomic force microscope of claim27 and additionally comprising:an inlet bore and an outlet bore in saidprobe-carrying module communicating between said fluid cell and theexterior of said probe-carrying module whereby fluid can be insertedinto said fluid cell.
 29. The atomic force microscope of claim 27 andadditionally comprising:(a) an electrode bore in said probe-carryingmodule communicating between said fluid cell and the exterior of saidprobe-carrying module; and, (b) an electrode disposed in said electrodebore having a first end within said fluid cell and a second end at theexterior of said probe-carrying module to which electrical connectioncan be made.
 30. The atomic force microscope of claim 27 andadditionally comprising:(a) three electrode bores in said probe-carryingmodule communicating between said fluid cell and the exterior of saidprobe-carrying module; and, (b) a working electrode, a referenceelectrode, and an auxiliary electrode disposed in said electrode bores,each of said electrodes having a first end within said fluid cell and asecond end at the exterior of said probe-carrying module to whichelectrical connection can be made.
 31. The atomic force microscope ofclaim 19 and additionally comprising:a voltage shield of an electricallyconductive material disposed over said top surface of said scan tube innon-electrical contact therewith, said voltage shield being electricallyconnected to a fixed voltage source whereby to shield said probe fromthe effects of said scanning voltages applied to said scan tube.
 32. Theatomic force microscope of claim 31 wherein:said fixed voltage source isground.
 33. The atomic force microscope of claim 19 and additionallycomprising:a slidably moveable and removable stage releasably attachedto said top surface of said scan tube for releasably and adjustablyholding a sample to be scanned attached thereto.
 34. The atomic forcemicrocscope of claim 33 wherein:(a) said stage contains a magnettherein; and additionally comprising, (b) a voltage shield of aferro-magnetic and electrically conductive material disposed over saidtop surface of said scan tube in non-electrical contact therewith, saidvoltage shield being electrically connected to a fixed voltage source toshield said probe from the effects of said scanning voltages applied tosaid scan tube and providing an attachment surface to which said stagecan magnetically attach and upon which it can slide.
 35. The atomicforce microscope of claim 33 wherein:(a) said stage is of aferro-magnetic material; and additionally comprising, (b) a voltageshield of an electrically conductive material disposed over said topsurface of said scan tube in non-electrical contact therewith, saidvoltage shield containing a magnet therein, being electrically connectedto a fixed voltage source to shield said probe from the effects of saidscanning voltages applied to said scan tube, and providing an attachmentsurface to which said stage can magnetically attach and upon which itcan slide.
 36. The atomic force microscope of claim 24 and additionallycomprising:first calibration means for positioning said member affixedto said bottom surface of said probe-carrying module as a function ofthe position of a tip position of said probe.
 37. The atomic forcemicroscope of claim 19 and additionally comprising:second calibrationmeans for setting the position of said sample holding block on saidfirst support means.
 38. The atomic force microscope of claim 19 andadditionally comprising:third calibration means for setting the positionof said probe-carrying module on said second support means.
 39. Anatomic force microscope containing an easily replaceable probe-carryingmember including an optional fluid cell comprising:(a) a horizontal basemember; (b) a scan tube vertically supported at a bottom end by saidbase member and having a top surface for holding a sample to be scannedand moveable in x-, y-, and z-directions as a result of scanningvoltages applied thereto; (c) first support means extending upward fromsaid base member; (d) a sample holding block having a chamber therein,said sample holding block having a first bore communicating with saidchamber through a bottom surface, a second bore communicating with saidchamber through a top surface, and a third bore communicating with saidchamber at an acute angle to said second bore, said sample holding blockbeing positioned with said scan tube passing through said first bore andsupported by said first support means; (e) second support meansextending upward from said bottom surface into said chamber; (f) aprobe-carrying module of an optically transparent material having topand bottom surfaces removably disposed in said chamber and supported bysaid second support means, said bottom surface having a probe attachedthereto and extending downward therefrom at an acute angle with respectto said bottom surface of said probe-carrying module and with a tip ofsaid probe positioned to contact a sample mounted on said top surface ofsaid scan tube, said probe-carrying module including an angled pad onsaid bottom surface thereof and said probe carried by saidprobe-carrying module comprising,(f1) a substrate attached to said pad,and (f2) an arm of a smooth-surfaced, minimally self-biased materialcantilevered outward from a bottom front edge of said substrate to forman optical lever, said arm having a probe point at an outer end thereof;(g) sealing means surrounding said probe and attached to said bottomsurface of said probe-carrying module for sealing to a top surface of asample to form a fluid cell around said probe; (h) a source of a laserbeam mounted for directing said laser beam down said second bore fromsaid top surface of said sample holding block to pass through saidprobe-carrying module, strike said probe, and be reflected back throughsaid probe-carrying module and down said third bore to an outer endthereof; and, (i) photoelectric sensor means having an active surfacepositioned over said outer end of said third bore for developing anelectrical signal at an output thereof reflecting the position of saidactive surface at which said laser beam strikes said active surface. 40.The atomic force microscope of claim 39 wherein:said first support meanscomprises three first adjusting screws threaded through said base memberwith said sample holding block resting on top ends thereof with one ofsaid top ends disposed in a slot in a flat bottom surface of said sampleholding block, another of said top ends disposed in a hole in saidbottom surface, and a third of said top ends disposed on said bottomsurface whereby said sample holding block is removable from said basemember and repeatedly replaceable to a pre-established position thereon.41. The atomic force microscope of claim 39 wherein:said second supportmeans comprises three second adjusting screws threaded through saidbottom surface of said sample holding block with said probe-carryingmodule resting on top ends thereof with one of said top ends disposed ina slot in a flat bottom surface of said probe-carrying module, anotherof said top ends disposed in a hole in a member affixed to said bottomsurface, and a third of said top ends disposed on said bottom surfacewhereby said probe-carrying module is removable from said chamber ofsaid sample holding block and repeatably replaceable to apre-established position therein.
 42. The atomic force microscope ofclaim 39 and additionally comprising:an inlet bore and an outlet bore insaid probe-carrying module communicating between said fluid cell and theexterior of said probe-carrying module whereby fluid can be insertedinto said fluid cell.
 43. The atomic force microscope of claim 39 andadditionally comprising:(a) an electrode bore in said probe-carryingmodule communicating between said fluid cell and the exterior of saidprobe-carrying module; and, (b) an electrode disposed in said electrodebore having a first end within said fluid cell and a second end at theexterior of said probe-carrying module to which electrical connectioncan be made.
 44. The atomic force microscope of claim 39 andadditionally comprising:(a) three electrode bores in said probe-carryingmodule communicating between said fluid cell and the exterior of saidprobe-carrying module; and, (b) a working electrode, a referenceelectrode, and an auxiliary electrode disposed in said electrode bores,each of said electrodes having a first end within said fluid cell and asecond end at the exterior of said probe-carrying module to whichelectrical connection can be made.
 45. The atomic force microscope ofclaim 39 and additionally comprising:a voltage shield of an electricallyconductive material disposed over said top surface of said scan tube innon-electrical contact therewith, said voltage shield being electricallyconnected to a fixed voltage source whereby to shield said probe fromthe effects of said scanning voltages applied to said scan tube.
 46. Theatomic force microscope of claim 39 and additionally comprising:aslidably moveable and removable stage releasably attached to said topsurface of said scan tube for releasably and adjustably holding a sampleto be scanned attached thereto.
 47. The atomic force microscope of claim46 wherein:(a) said stage contains a magnet therein; and additionallycomprising, (b) a voltage shield of a ferro-magnetic and electricallyconductive material disposed over said top surface of said scan tube innon-electrical contact therewith, said voltage shield being electricallyconnected to a fixed voltage source to shield said probe from theeffects of said scanning voltages applied to said scan tube andproviding an attachment surface to which said stage can magneticallyattach and upon which it can slide.
 48. The atomic force microscope ofclaim 46 wherein:(a) said stage is of a ferro-magnetic material; andadditionally comprising, (b) a voltage shield of an electricallyconductive material disposed over said top surface of said scan tube innon-electrical contact therewith, said voltage shield containing amagnet therein, being electrically connected to a fixed voltage sourceto shield said probe from the effects of said scanning voltages appliedto said scan tube, and providing an attachment surface to which saidstage can magnetically attach and upon which it can slide.
 49. An atomicforce microscope including an fluid cell surrounding a scanning probefor preventing damage to a scanned sample and the scanning probecomprising:(a) a horizontal base member; (b) a scan tube verticallysupported at a bottom end by said base member and having a top surfacefor holding a sample to be scanned and moveable in x-, y-, andz-directions as a result of scanning voltages applied thereto; (c) aprobe-carrying module disposed above said top surface of said scan tubeand having a probe attached thereto and extending downward therefromwith a tip of said probe positioned to contact a sample mounted on saidtop surface of said scan tube; (d) means for sensing movement of saidprobe and for providing an electrical signal at an output thereofreflecting said movement of said probe; and, (e) fluid cell formingmeans carried by said probe-carrying module for forming a fluid cellaround said probe on a top surface of a sample mounted on said topsurface of said scan tube when filled with a fluid.
 50. The atomic forcemicroscope of claim 49 wherein:said fluid cell forming means comprises acover glass disposed over said probe and close enough to said topsurface of said sample to maintain a drop of fluid between said topcover glass and said surface of said sample around said probe bycapillary action.
 51. The atomic force microscope of claim 49wherein:said fluid cell forming means comprises annular sealing meanssurrounding said probe and attached to a bottom surface of saidprobe-carrying module for sealing to said top surface of said sample toform a fluid cell around said probe.
 52. The atomic force microscope ofclaim 51 and additionally comprising:an inlet bore and an outlet bore insaid probe-carrying module communicating between said fluid cell and theexterior of said probe-carrying module whereby fluid can be insertedinto said fluid cell.
 53. The atomic force microscope of claim 51 andadditionally comprising:(a) an electrode bore in said probe-carryingmodule communicating between said fluid cell and the exterior of saidprobe-carrying module; and, (b) an electrode disposed in said electrodebore having a first end within said fluid cell and a second end at theexterior of said probe-carrying module to which electrical connectioncan be made.
 54. The atomic force microscope of claim 51 andadditionally comprising:(a) three electrode bores in said probe-carryingmodule communicating between said fluid cell and the exterior of saidprobe-carrying module; and, (b) a working electrode, a referenceelectrode, and an auxiliary electrode disposed in said electrode bores,each of said electrodes having a first end within said fluid cell and asecond end at the exterior of said probe-carrying module to whichelectrical connection can be made.
 55. The atomic force microscope ofclaim 51 and additionally comprising:a voltage shield of an electricallyconductive material disposed over said top surface of said scan tube innon-electrical contact therewith, said voltage shield being electricallyconnected to a fixed voltage source whereby to shield said probe fromthe effects of said scanning voltages applied to said scan tube.
 56. Theatomic force microscope of claim 51 and additionally comprising:aslidably moveable and removable stage releasably attached to said topsurface of said scan tube for releasably and adjustably holding a sampleto be scanned attached thereto.
 57. The atomic force microscope of claim56 wherein:(a) said stage contains a magnet therein; and additionallycomprising: (b) a voltage shield of a ferro-magnetic and electricallyconductive material disposed over said top surface of said scan tube innon-electrical contact therewith, said voltage shield being electricallyconnected to a fixed voltage source to shield said probe from theeffects of said scanning voltages applied to said scan tube andproviding an attachment surface to which said stage can magneticallyattach and upon which it can slide.
 58. The atomic force microscope ofclaim 56 wherein:(a) said stage is of a ferro-magnetic material; andadditionally comprising, (b) a voltage shield of an electricallyconductive material disposed over said top surface of said scan tube innon-electrical contact therewith, said voltage shield containing amagnet therein, being electrically connected to a fixed voltage sourceto shield said probe from the effects of said scanning voltages appliedto said scan tube, and providing an attachment surface to which saidstage can magnetically attach and upon which it can slide. .Iadd.59. Anatomic force microscope for determining a characteristic of a sample,comprising: a probe adapted to scan said sample; scanning means forcausing relative scanning movement between said probe and said sample;sensing means for sensing a position of said probe; and a non-cryogenicfluid body in communication with said sample and in which said probe isimmersed in contact with said sample so that during said relativescanning movement capillary attraction between said probe and saidsample, caused by a surface film formed on said sample due to exposureto ambient atmosphere, is reduced. .Iaddend. .Iadd.60. The atomic forcemicroscope according to claim 59, further comprising: a rigid coverplate disposed on a top surface of said fluid body to define a fluidcell between said cover plate and said sample. .Iaddend..Iadd.61. Theatomic force microscope according to claim 60, wherein: said rigid coverplate comprises an optically transparent material; and said sensingmeans comprises optical means for sensing a vertical movement of saidprobe by means of light applied to said probe through said rigid coverplate. .Iaddend. .Iadd.62. The atomic force microscope according toclaim 59, comprising: means for exchanging fluid within said fluid body..Iaddend. .Iadd.63. The atomic force microscope according to claim 59,further comprising; two or more electrodes in contact with said fluidbody for performing an electrochemical reaction. .Iaddend. .Iadd.64. Theatomic force microscope according to claim 60, further comprising; twoor more electrodes in contact with said fluid body for performing anelectrochemical reaction. .Iaddend. .Iadd.65. The atomic forcemicroscope according to claim 61, further comprising; two or moreelectrodes in contact with said fluid body for performing anelectrochemical reaction. .Iaddend. .Iadd.66. The atomic forcemicroscope according to claim 62, further comprising; two or moreelectrodes in contact with said fluid body for performing anelectrochemical reaction. .Iaddend. .Iadd.67. The atomic forcemicroscope according to claim 59, wherein said scanning means comprises:a scanner; and a conductive shield element at a fixed potential disposedbetween said probe and said scanner for electrically shielding saidprobe from said scanner. .Iaddend. .Iadd.68. The atomic force microscopeaccording to claim 60, wherein said scanning means comprises: a scanner;and a conductive shield element at a fixed potential disposed betweensaid probe and said scanner for electrically shielding said probe fromsaid scanner. .Iaddend. .Iadd.69. The atomic force microscope accordingto claim 61, wherein said scanning means comprises: a scanner; and aconductive shield element at a fixed potential disposed between saidprobe and said scanner for electrically shielding said probe from saidscanner. .Iaddend. .Iadd.70. The atomic force microscope according toclaim 62, wherein said scanning means comprises: a scanner; and aconductive shield element at a fixed potential disposed between saidprobe and said scanner for electrically shielding said probe from saidscanner. .Iaddend. .Iadd.71. The atomic force microscope according toclaim 63, wherein said scanning means comprises: a scanner; and aconductive shield element at a fixed potential disposed between saidprobe and said scanner for electrically shielding said probe from saidscanner. .Iaddend. .Iadd.72. The atomic force microscope according toclaim 64, wherein said scanning means comprises: a scanner; and aconductive shield element at a fixed potential disposed between saidprobe and said scanner for electrically shielding said probe from saidscanner. .Iaddend. .Iadd.73. The atomic force microscope according toclaim 65, wherein said scanning means comprises: a scanner; and aconductive shield element at a fixed potential disposed between saidprobe and said scanner for electrically shielding said probe from saidscanner. .Iaddend. .Iadd.74. The atomic force microscope according toclaim 66, wherein said scanning means comprises: a scanner; and aconductive shield element at a fixed potential disposed between saidprobe and said scanner for electrically shielding said probe from saidscanner. .Iaddend. .Iadd.75. The atomic force microscope according toclaim 59, further comprising: a removable probe module on which saidprobe is fixedly mounted at a selected location. .Iaddend. .Iadd.76. Theatomic force microscope according to claim 75, further comprising: aprobe module support mechanically coupled to said probe module duringoperation of said atomic force microscope and having a predeterminedspatial arrangement with said sensing means so that when said probemodule is mechanically coupled to said probe module support, said probeis in substantial alignment with said sensing means. .Iaddend. .Iadd.77.The atomic force microscope according to claim 61, further comprising: aremovable probe module on which said probe is fixedly mounted at aselected location. .Iaddend. .Iadd.78. The atomic force microscopeaccording to claim 77, further comprising: a probe module supportmechanically coupled to said probe module during operation of saidatomic force microscope and having a predetermined spatial arrangementwith said sensing means so that when said probe module is mechanicallycoupled to said probe module support, said probe is in substantialalignment with said sensing means. .Iaddend. .Iadd.79. The atomic forcemicroscope according to claim 62, further comprising: a removable probemodule on which said probe is fixedly mounted at a selected location..Iaddend. .Iadd.80. The atomic force microscope according to claim 79,further comprising: a probe module support mechanically coupled to saidprobe module during operation of said atomic force microscope and havinga predetermined spatial arrangement with said sensing means so that whensaid probe module is mechanically coupled to said probe module support,said probe is in substantial alignment with said sensing means..Iaddend. .Iadd.81. The atomic force microscope according to claim 63,further comprising: a removable probe module on which said probe isfixedly mounted at a selected location. .Iaddend. .Iadd.82. The atomicforce microscope according to claim 81, further comprising: a probemodule support mechanically coupled to said probe module duringoperation of said atomic force microscope and having a predeterminedspatial arrangement with said sensing means so that when said probemodule is mechanically coupled to said probe module support, said probeis in substantial alignment with said sensing means. .Iaddend. .Iadd.83.The atomic force microscope according to claim 65, further comprising: aremovable problem module on which said probe is fixedly mounted at aselected location. .Iaddend. .Iadd.84. The atomic force microscopeaccording to claim 83, further comprising: a probe module supportmechanically coupled to said probe module during operation of saidatomic force microscope and having a predetermined spatial arrangementwith said sensing means so that when said probe module is mechanicallycoupled to said probe module support, said probe is in substantialalignment with said sensing means. .Iaddend. .Iadd.85. The atomic forcemicroscope according to claim 66, further comprising: a removable probemodule on which said probe is fixedly mounted at a selected location..Iaddend. .Iadd.86. The atomic force microscope according to claim 85,further comprising: a probe module support mechanically coupled to saidprobe module during operation of said atomic force microscope and havinga predetermined spatial arrangement with said sensing means so that whensaid probe module is mechanically coupled to said probe module support,said probe is in substantial alignment with said sensing means..Iaddend. .Iadd.87. The atomic force microscope according to claim 67,further comprising: a removable probe module on which said probe isfixedly mounted at a selected location. .Iaddend. .Iadd.88. The atomicforce microscope according to claim 87, further comprising: a probemodule support mechanically coupled to said probe module duringoperation of said atomic force microscope and having a predeterminedspatial arrangement with said sensing means so that when said probemodule is mechanically coupled to said probe module support, said probeis in substantial alignment with said sensing means. .Iaddend. .Iadd.89.The atomic force microscope according to claim 69, further comprising: aremovable probe module on which said probe is fixedly mounted at aselected location. .Iaddend. .Iadd.90. The atomic force microscopeaccording to claim 89, further comprising: a probe module supportmechanically coupled to said probe module during operation of saidatomic force microscope and having a predetermined spatial arrangementwith said sensing means so that when said probe module is mechanicallycoupled to said probe module support, said probe is in substantialalignment with said sensing means. .Iaddend. .Iadd.91. The atomic forcemicroscope according to claim 70, further comprising: a removable probemodule on which said probe is fixedly mounted at a selected location..Iaddend. .Iadd.92. The atomic force microscope according to claim 91,further comprising: a probe module support mechanically coupled to saidprobe module during operation of said atomic force microscope and havinga predetermined spatial arrangement with said sensing means so that whensaid probe module is mechanically coupled to said probe module support,said probe is in substantial alignment with said sensing means..Iaddend. .Iadd.93. The atomic force microscope according to claim 71,further comprising: a removable probe module on which said probe isfixedly mounted at a selected location. .Iaddend. .Iadd.94. The atomicforce microscope according to claim 93, further comprising: a probemodule support mechanically coupled to said probe module duringoperation of said atomic force microscope and having a predeterminedspatial arrangement with said sensing means so that when said probemodule is mechanically coupled to said probe module support, said probeis in substantial alignment with said sensing means. .Iaddend. .Iadd.95.The atomic force microscope according to claim 72, further comprising: aremovable probe module on which said probe is fixedly mounted at aselected location. .Iaddend. .Iadd.96. The atomic force microscopeaccording to claim 95, further comprising: a probe module supportmechanically coupled to said probe module during operation of saidatomic force microscope and having a predetermined spatial arrangementwith said sensing means so that when said probe module is mechanicallycoupled to said probe module support, said probe is in substantialalignment with said sensing means. .Iaddend. .Iadd.97. The atomic forcemicroscope according to claim 73, further comprising: a removable probemodule on which said probe is fixedly mounted at a selected location..Iaddend. .Iadd.98. The atomic force microscope according to claim 97,further comprising: a probe module support mechanically coupled to saidprobe module during operation of said atomic force microscope and havinga predetermined spatial arrangement with said sensing means so that whensaid probe module is mechanically coupled to said probe module support,said probe is in substantial alignment with said sensing means..Iaddend. .Iadd.99. The atomic force microscope according to claim 74,further comprising: a removable probe module on which said probe isfixedly mounted at a selected location. .Iaddend. .Iadd.100. The atomicforce microscope according to claim 99, further comprising: a probemodule support mechanically coupled to said probe module duringoperation of said atomic force microscope and having a predeterminedspatial arrangement with said sensing means so that when said probemodule is mechanically coupled to said probe module support, said probeis in substantial alignment with said sensing means. .Iaddend..Iadd.101. The atomic force microscope according to claim 59, furthercomprising: a slidably moveable and removable sample support releasablycoupled to said scanning means and on which said sample is mounted..Iaddend. .Iadd.102. The atomic force microscope according to claim 101,further comprising: magnetic means for magnetically mechanicallycoupling said sample support to said scanning means. .Iaddend..Iadd.103. The atomic force microscope according to claim 60, furthercomprising: a slidably moveable and removable sample support releasablycoupled to said scanning means and on which said sample is mounted..Iaddend. .Iadd.104. The atomic force microscope according to claim 103,further comprising: magnetic means for magnetically mechanicallycoupling said sample support to said scanning means. .Iaddend..Iadd.105. The atomic force microscope according to claim 63, furthercomprising: a slidably moveable and removable sample support releasablycoupled to said scanning means and on which said sample is mounted..Iaddend. .Iadd.106. The atomic force microscope according to claim 105,further comprising: magnetic means for magnetically mechanicallycoupling said sample support to said scanning means. .Iaddend..Iadd.107. The atomic force microscope according to claim 67, furthercomprising: a slidably moveable and removable sample support releasablycoupled to said scanning means and on which said sample is mounted..Iaddend. .Iadd.108. The atomic force microscope according to claim 107,further comprising: magnetic means for magnetically mechanicallycoupling said sample support to said scanning means. .Iaddend..Iadd.109. The atomic force microscope according to claim 76, furthercomprising: a slidably moveable and removable sample support releasablycoupled to said scanning means and on which said sample is mounted..Iaddend. .Iadd.110. The atomic force microscope according to claim 109,further comprising: magnetic means for magnetically mechanicallycoupling said sample support to said scanning means. .Iaddend..Iadd.111. The atomic force microscope according to claim 87, furthercomprising: a slidably moveable and removable sample support releasablycoupled to said scanning means and on which said sample is mounted..Iaddend. .Iadd.112. The atomic force microscope according to claim 111,further comprising: magnetic means for magnetically mechanicallycoupling said sample support to said scanning means. .Iaddend..Iadd.113. The atomic force microscope according to claim 59,comprising: a support on which said sensing means is mounted; and meansmounted on said support for adjusting positioning of said sensing means..Iaddend. .Iadd.114. The atomic force microscope according to claim 113,comprising: said sensing means comprising a light beam source and alight beam detector; and said adjusting means comprising means foradjusting positioning of at least one of said light beam source and saidlight beam detector so that a light beam output by said source andreflected of said probe is incident on said detector. .Iaddend..Iadd.115. The atomic force microscope according to claim 60,comprising: a support on which said sensing means is mounted; and meansmounted on said support for adjusting positioning of said sensing means..Iaddend. .Iadd.116. The atomic force microscope according to claim 115,comprising: said sensing means comprising a light beam source and alight beam detector; and said adjusting means comprising means foradjusting positioning of at least one of said light beam source and saidlight beam detector so that a light beam output by said source andreflected of said probe is incident on said detector. .Iaddend..Iadd.117. The atomic force microscope according to claim 63,comprising: a support on which said sensing means is mounted; and meansmounted on said support for adjusting positioning of said sensing means..Iaddend. .Iadd.118. The atomic force microscope according to claim 117,comprising: said sensing means comprising a light beam source and alight beam detector; and said adjusting means comprising means foradjusting positioning of at least one of said light beam source and saidlight beam detector so that a light beam output by said source andreflected of said probe is incident on said detector. .Iaddend..Iadd.119. The atomic force microscope according to claim 67,comprising: a support on which said sensing means is mounted; and meansmounted on said support for adjusting positioning of said sensing means..Iaddend. .Iadd.120. The atomic force microscope according to claim 119,comprising: said sensing means comprising a light beam source and alight beam detector; and said adjusting means comprising means foradjusting positioning of at least one of said light beam source and saidlight beam detector so that a light beam output by said source andreflected of said probe is incident on said detector. .Iaddend..Iadd.121. The atomic force microscope according to claim 76,comprising: a support on which said sensing means is mounted; and meansmounted on said support for adjusting positioning of said sensing means..Iaddend. .Iadd.122. The atomic force microscope according to claim 121,comprising: said sensing means comprising a light beam source and alight beam detector; and said adjusting means comprising means foradjusting positioning of at least one of said light beam source and saidlight beam detector so that a light beam output by said source andreflected of said probe is incident on said detector. .Iaddend..Iadd.123. The atomic force microscope according to claim 87,comprising: a support on which said sensing means is mounted; and meansmounted on said support for adjusting positioning of said sensing means..Iaddend. .Iadd.124. The atomic force microscope according to claim 123,comprising: said sensing means comprising a light beam source and alight beam detector; and said adjusting means comprising means foradjusting positioning of at least one of said light beam source and saidlight beam detector so that a light beam output by said source andreflected of said probe is incident on said detector. .Iaddend..Iadd.125. The atomic force microscope according to claim 106,comprising: a support on which said sensing means is mounted; and meansmounted on said support for adjusting positioning of said sensing means..Iaddend. .Iadd.126. The atomic force microscope according to claim 125,comprising: said sensing means comprising a light beam source and alight beam detector; and said adjusting means comprising means foradjusting positioning of at least one of said light beam source and saidlight beam detector so that a light beam output by said source andreflected of said probe is incident on said detector. .Iaddend..Iadd.127. In an atomic force microscope having a deflection detectionsystem for detecting a deflection of a lever mounted probe as said probeis scanned across a surface of a sample by a means for scanning thesample, the improvement comprising: a non-cryogenic fluid body incommunication with said surface of the sample and in which said probe isimmersed in contact with said sample while said probe is scanned acrossthe surface of the sample. .Iaddend. .Iadd.128. The atomic forcemicroscope according to claim 127, further comprising: a rigid coverplate disposed on a top surface of said fluid body to define a fluidcell between said cover plate and said sample. .Iaddend. .Iadd.129. Theatomic force microscope according to claim 128, wherein: said rigidcover plate comprises an optically transparent material; and saiddeflection detection system comprises optical means for sensing avertical movement of said probe by means of light applied to said probethrough said rigid cover plate. .Iaddend. .Iadd.130. The atomic forcemicroscope according to claim 127, further comprising: two or moreelectrodes in contact with said fluid body for performing anelectrochemical reaction. .Iaddend. .Iadd.131. In an atomic forcemicroscope having a deflection detection system for detecting adeflection of a lever mounted probe as said probe is scanned across asurface of a sample, the improvement comprising: a scanner for scanningsaid probe; and a conductive shield at a fixed potential disposedbetween said probe and said scanner. .Iaddend. .Iadd.132. The atomicforce microscope according to claim 131, wherein said scanner comprisesa piezoelectric tube and said conductive shield is mounted on a distalend of said tube between said tube and said probe. .Iaddend. .Iadd.133.In a method of operating an atomic force microscope in which a levermounted probe is scanned across the surface of a sample by a scanner anda deflection of said lever mounted probe is detected by a deflectiondetection system, the improvement comprising: providing a fluid body incommunication with the surface of the sample and not in communicationwith said scanner; immersing said lever mounted probe in said fluidbody; and scanning said lever mounted probe across the suface of thesample while said lever mounted probe is immersed in said fluid body..Iaddend. .Iadd.134. The method according to claim 133, comprising:placing two or more electrodes in contact with said fluid body; andapplying a voltage across said electrodes during said scanning step toproduce an electrochemical reaction in said fluid. .Iaddend. .Iadd.135.In an atomic force microscope having a deflection detection system fordetecting a deflection of a lever mounted probe as said probe is scannedacross a surface of a sample, the improvement comprising: a removableprobe module on which said probe fixedly mounted at a selected location;and a probe module support mechanically coupled to said probe moduleduring operation of said atomic force microscope and having apredetermined spatial arrangement with said deflection detection systemso that when said probe module is mechanically coupled to said probemodule support, said probe is in substantial alignment with saiddeflection detection system. .Iaddend. .Iadd.136. In an atomic forcemicroscope having a deflection detection system for detecting adeflection of a lever mounted probe as said probe is scanned across asurface of a sample by a means for scanning the sample, the improvementcomprising: a slidably moveable and removable sample support releasablycoupled to said scanning means and on which said sample is mounted..Iaddend. .Iadd.137. The atomic force microscope according to claim 136,further comprising: magnetic means for magnetically mechanicallycoupling said sample support to said scanning means. .Iaddend..Iadd.138. In an atomic force microscope having a deflection detectionssystem for detecting deflection of a lever mounted probe as said probeis scanned by a scanner across a surface of a sample, the improvementcomprising: a support on which said deflection detection system and saidprobe are mounted; and means mounted on said support for adjustingpositioning of said deflection detection system. .Iaddend. .Iadd.139.The atomic force microscope according to claim 138, further comprising:said deflection detection system comprising a light beam source and alight beam detector; and said adjusting means comprising means foradjusting positioning of at least one of said light beam source and saidlight beam detector so that a light beam output by said source andreflected off said probe is incident on said detector. .Iaddend.